ruby-changes:58887
From: John <ko1@a...>
Date: Sat, 23 Nov 2019 05:42:57 +0900 (JST)
Subject: [ruby-changes:58887] 26fd8d962c (master): Optimize pinned page sorting
https://git.ruby-lang.org/ruby.git/commit/?id=26fd8d962c From 26fd8d962ce42b7eb8d1c1eb43ddfa1ff24dc3aa Mon Sep 17 00:00:00 2001 From: John Hawthorn <john@h...> Date: Wed, 20 Nov 2019 14:18:40 -0800 Subject: Optimize pinned page sorting Previously we would count the pinned objects on each comparison. Since sorting is O(N log N) and we calculated this on both left and right pages on each comparison this resulted in a extra iterations over the slots. diff --git a/gc.c b/gc.c index 9329f31..d2b4330 100644 --- a/gc.c +++ b/gc.c @@ -844,6 +844,7 @@ enum { https://github.com/ruby/ruby/blob/trunk/gc.c#L844 struct heap_page { short total_slots; short free_slots; + short pinned_slots; short final_slots; struct { unsigned int before_sweep : 1; @@ -7731,9 +7732,13 @@ count_pinned(struct heap_page *page) https://github.com/ruby/ruby/blob/trunk/gc.c#L7732 static int compare_pinned(const void *left, const void *right, void *dummy) { - int left_count = count_pinned(*(struct heap_page * const *)left); - int right_count = count_pinned(*(struct heap_page * const *)right); - return right_count - left_count; + struct heap_page *left_page; + struct heap_page *right_page; + + left_page = *(struct heap_page * const *)left; + right_page = *(struct heap_page * const *)right; + + return right_page->pinned_slots - left_page->pinned_slots; } static int @@ -7760,6 +7765,7 @@ allocate_page_list(rb_objspace_t *objspace, page_compare_func_t *comparator) https://github.com/ruby/ruby/blob/trunk/gc.c#L7765 list_for_each(&heap_eden->pages, page, page_node) { page_list[i++] = page; + page->pinned_slots = count_pinned(page); GC_ASSERT(page != NULL); } GC_ASSERT(total_pages > 0); -- cgit v0.10.2 -- ML: ruby-changes@q... Info: http://www.atdot.net/~ko1/quickml/